There were heaps of rubble and chunks of shattered concrete at the scene, which a large crowd of what appeared to be local residents were helping to clear.

Hospital scenes

At a local hospital, reporters were shown three bodies, including a child, which government officials said were people killed in the air strike.

One of the bodies was covered with debris and dust. Reporters were also shown a wounded child.

"Basically, this is another night of murder, terror and horror in Tripoli caused by NATO," Moussa Ibrahim, a government spokesman, said at the hospital. Five families were living in the building which was hit, he said.

It could not be immediately verified whether the three bodies had come from the destroyed building.

The most recent figures from Libya's health ministry show 856 civilians have been killed in NATO air raids since they began in March. The figure could not be independently confirmed.

Previous government-announced tolls from individual attacks have proven to be exaggerated.

NATO, which has a mandate to protect Libyan civilians, has been stepping up the pressure on Muammar Gaddafi as a four-month uprising devolved into a civil war. It rejects allegations it targets civilians.

Strains are appearing within NATO member states as the campaign drags on for longer than envisaged and Gaddafi remains in power - even making a show of defiance last week by playing chess with a visiting official.

Mistaken attack

Late on Saturday, NATO announced that it had mistakenly struck a column of Libyan rebel vehicles in an air attack near an eastern oil town two days earlier and expressed regret for any casualties that might have resulted.

The alliance has accidentally hit rebel forces before in its air campaign to protect civilians.

The rebels have complained that NATO's raids have not helped them gain decisive momentum against the Libyan leader's better trained and equipped military.

The alliance statement gave no figures on casualties from Thursday's raid, but said it regretted "any possible loss of life or injuries caused by this unfortunate incident".

International military forces have had some trouble in hitting government troops because of their proximity to civilians. Government troops have also used civilian vehicles, making them difficult to distinguish from rebel forces.

A doctor in the nearby city of Ajdabiya said the bodies of four rebel fighters were brought to his hospital around the time of Thursday's attack, but it was not possible to confirm whether they were killed in the bombardment.

After four months of civil war, rebels control much of the east of Libya, the area around the western port city of Misurata and much of the western mountain region stretching to the border with Tunisia.